The Lost Boy ~The tale of Will Cipher~
This story takes place one year later after the mystery twins' crazy summer in Gravity Falls. Summer has finally come again, and they are staying with Stan, Ford and the rest of the gang for another summer. As Dipper Pines is exploring in the forest with Ford's journal one day., he hears a soft noise, like somebody crying.... He finds a fifteen and a half year old boy tied up in the forest, crying an awful lot. He eventually takes him back to the Mystery Shack to find out who knows what, you will have to read to find out.
NOTE: I DO NOT OWN GRAVITY FALLS OR ANY OF ITS CONTENT BUT I DO OWN THIS BOOK!!!